镁合金LPSO/SFs结构间{1012}孪晶交汇机制的原子尺度研究  

Unravelling the{1012}Twin Intersection Between LPSO Structure/SFs in Magnesium Alloy

作　　者：邵晓宏[1] 彭珍珍 靳千千 马秀良[1] SHAO Xiaohong;PENG Zhenzhen;JIN Qianqian;MA Xiuliang(Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,Hebei University of Science and Technology,Shijiazhuang 050018,China;Center for the Structure of Advanced Matter,School of Electronic Engineering,Guangxi University of Science and Technology,Liuzhou 545006,China)

机构地区：[1]中国科学院金属研究所沈阳材料科学国家研究中心,沈阳110016 [2]河北科技大学材料科学与工程学院,石家庄050018 [3]广西科技大学电子工程学院先进物质结构研究中心,柳州545006

出　　处：《金属学报》2023年第4期556-566,共11页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.51871222和52171021。

摘　　要：以含长周期堆垛有序(LPSO)结构的Mg-Zn-Y(-Zr)合金为研究对象,运用透射电子显微方法,从原子尺度解析LPSO结构/富含溶质元素堆垛层错(SFs)对{1012}孪晶交汇行为的作用。结果表明:LPSO/SFs与孪晶交截处易形成基面-棱柱面,从而引起孪晶界在LPSO/SFs间弯曲成弓形,孪晶界存在Zn元素偏聚,Y元素偏聚不明显。LPSO/SFs间同轴{1012}孪晶变体交汇,引入基面-基面(BB)界面及柱面-柱面(PP)界面,且在近LPSO/SFs处产生三角形的局部基体结构。LPSO结构形成扭折时,{1012}孪晶在扭折界面单侧形核长大,此处扭折界面转为孪晶界面;残余扭折界面与基体侧孪晶扩展界面相交,在LPSO/SFs近邻处形成三角形的基体结构。LPSO/SFs/TSFs(孪晶层错)间不同孪晶变体形核,以及交汇引入的分割带来的Hall-Petch效应,可提升合金的硬化率。通过调控镁合金LPSO结构的间距和厚度引入不同孪晶变体,可为其优化性能提供新思路。The effect of long-period stacking ordered(LPSO)structure/solute-rich element laminar stacking faults(SFs)on the intersection of co-zone{1012}twin variants was uncovered at the atomic scale by TEM.The results show that a basal-prismatic(BP)boundary is generally formed at the intersection of LPSO/SFs and twins,bending the twin boundaries(TBs)into a bow shape between the adjacent LPSO/SFs.The co-zone{1012}twin variants and LPSO/SFs intersect with each other,introducing a basalbasal(BB)boundary and prismatic-prismatic(PP)boundaries,associated with a triangular matrix near the LPSO/SFs.More Zn atoms than Y atoms were segregated into the TBs.Also,when the LPSO structure is kinked,the{1012}twin generates and grows on one side of the kink boundary,and the local kink boundary transforms into TB.The growing TB intersects with the residual kink boundary,leaving a triangular matrix near the LPSO/SFs.Multiple twin variants nucleate between the LPSO/SFs/TSFs(twinned stacking faults),and the associated Hall-Petch effect is brought by the segmentation introduced by the intersecting of variants,which can improve the Mg alloy hardening rate.Introducing different twin variants by regulating the LPSO structure􀆳s spacing and thickness in magnesium alloy may shed new light on optimizing their performance.

关 键 词：镁合金 LPSO结构 孪晶 球差校正扫描透射电镜 原子尺度 

分 类 号：TG146.2[一般工业技术—材料科学与工程]